KINSHASA, July 22 (Reuters) - Unidentified gunmen attacked a major military base in Democratic Republic of Congo's capital, Kinshasa, on Tuesday but the government said the situation had been quickly brought under control.

Witnesses said shooting died down after about half an hour but security forces deployed tanks on the streets. The base, known as Camp Tshatshi, was the scene of fighting in December last year when gunmen also attacked state television and an airport in the capital.

"Armed men attacked Camp Tshatshi some time between 1400 and 1430 (1300-1330 GMT) but they were defeated. We must await the preliminary reports before we can identify them," government spokesman Lambert Mende told Reuters.

A soldier in the camp who asked not to be named said at least four attackers had been killed.

President Joseph Kabila scored a major victory last year when his U.N.-backed forces defeated eastern rebels. However, he does not have a strong grip on the vast nation and there are increased tensions over whether Kabila will try to modify the constitution to stay in power for a third term in 2016.

(Reporting by Pete Jones; Writing by David Lewis Editing by Jeremy Gaunt)